Regular Expressions 101

Save & Share

  • Regex Version: ver. 2
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gmi

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"^=\?UTF-8\?Q\?(?=.*=E.=..=..)(?=.*[^=]*)?.*\?="; string input = @"=?UTF-8?q?=E5=8F=A3=E5=BA=A7=E6=83=85=E5=A0=B1=E7=A2=BA=E8=AA=8D=E3=81=AE?= =?UTF-8?q?ANA=E3=83=9E=E3=82=A4=E3=83=AC=E3=83=BC=E3=82=B8=E3=82=AF?= =?UTF-8?q?=E3=81=84=E3=80=91ANA=E3=83=9E=E3=82=A4=E3=83=AC=E3=83=BC?= =?UTF-8?q?=E3=80=90=E3=81=94=E7=A2=BA=E8=AA=8D=E3=81=8F=E3=81=A0=E3=81=95?= =?UTF-8?q?=E3=81=84=E3=80=91ANA=E3=83=9E=E3=82=A4=E3=83=AC=E3=83=BC?= =?UTF-8?q?=E3=82=B8=E3=82=AF=E3=83=A9=E3=83=96=EF=BC=9A=E6=9C=AA=E5=8A=A0?= =?UTF-8?q?=E7=AE=97=E3=83=9E=E3=82=A4=E3=83=AB=E3=81=AE=E6=89=8B=E7=B6=9A?= =?UTF-8?q?=E3=81=8D=E6=A1=88=E5=86=85=EF=BC=88=E3=83=A1=E3=83=BC=E3=83=AB?= =?UTF-8?q?=E7=95=AA=E5=8F=B7:CF-FC-01194167741=EF=BC=89?= =?UTF-8?q?=E5=8F=A3=E5=BA=A7=E5=8F=96=E5=BC=95=E5=88=B6=E9=99=90=E3=81=AE?= =?UTF-8?q?=E3=81=94=E6=A1=88=E5=86=85=EF=BC=9A=E3=82=AA=E3=83=AA=E3=82=B3?= =?UTF-8?q?=E6=83=85=E5=A0=B1=E3=82=92=E6=9B=B4=E6=96=B0=E3=81=97=E3=81=A6?= =?UTF-8?q?=E3=81=8F=E3=81=A0=E3=81=95=E3=81=84=E2=97=89PU-89581655388?= =?UTF-8?q?hello?= "; RegexOptions options = RegexOptions.Multiline | RegexOptions.IgnoreCase; foreach (Match m in Regex.Matches(input, pattern, options)) { Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index); } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx